Controlling Carpenter Bees

“They’re h-e-r-e again! Those annoying bees appear every spring and drill precise holes about the size of a dime in a variety of wooden structures or trim. Having tried a variety of control methods, is there a silver bullet or magic wand to keep these things away from my house and yard?”

Close-up of Carpenter bee (Xylocopa virginica)

Aptly named, Carpenter bees (Xylocopa virginica), often confused with Bumblebees, are those flying insects known for drilling extremely neat holes in wooden structures. Excavated by the female, who creates the holes and associated tunnels for shelter and “nurseries” where young are raised, damage to wood is normally of little significance. However, if allowed to continue activities year after year in the same location, there could be noticeable structural damage.

Sadly, their pollinating activities are usually overshadowed by the nesting urge of females to tunnel in wooden decks, porches, windowsills, railings, and lawn furniture. So first step in slowing down their interest in your property is to paint or stain anything made of wood, including cedar, cypress, or redwood. If that doesn’t work, you might try trapping them.

Carpenter bee trap. Photo by Sallie Lee

Many online sites offer Carpenter bee traps for sale or instruction for DIY; this trap was built by a homeowner using a block of untreated wood, a ½” drill bit, two screws, and an empty soda bottle.

Treating holes made by the female involves applying an insecticide directly into the opening, using a dust or spray. Allow the bees to pass through the entrance and wait for a couple of days, then fill holes with wood putty or caulk. Applying paint or a couple layers of stain will help prevent a new generation of carpenter bees from re-using the site next year.

The Alabama Cooperative Extension System (ACES) operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities. ACES is committed to affirmative action, equal opportunity and the diversity of its workforce. Educational programs of ACES serve all people regardless of race, color, age, sex, religion, disability, sexual orientation, or national origin.

The Alabama Cooperative Extension System operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities and answers home-gardeners' questions each week on Birmingham Gardening Today.

2 thoughts on “Controlling Carpenter Bees”

Applying almond oil or extract at the entry holes bored by the carpenter bees has been known to discourage their entry. Applying paint, varnish and polyurethane (not stain) has been shown to also be an effective deterrent. Finally, applying aluminum, vinyl siding or screen over the wood is effective. Visit http://www.carpenter-bee-trap.com for more information regarding the control of carpenter bees using pesticides and natural agents.